21768190 has 16 divisors (see below), whose sum is σ = 39404880. Its totient is φ = 8657920.

The previous prime is 21768179. The next prime is 21768199. The reversal of 21768190 is 9186712.

It is a happy number.

It is a super-2 number, since 2×21768190² = 947708191752200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21768199) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4291 + ... + 7870.

It is an arithmetic number, because the mean of its divisors is an integer number (2462805).

Almost surely, 2^21768190 is an apocalyptic number.

21768190 is a deficient number, since it is larger than the sum of its proper divisors (17636690).

21768190 is a wasteful number, since it uses less digits than its factorization.

21768190 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12347.

The product of its (nonzero) digits is 6048, while the sum is 34.

The square root of 21768190 is about 4665.6392916727. The cubic root of 21768190 is about 279.2163034434.

The spelling of 21768190 in words is "twenty-one million, seven hundred sixty-eight thousand, one hundred ninety".